Coexistence of Nematic Order and Superconductivity in the Hubbard Model

TL;DR

This paper investigates the coexistence of nematic order and superconductivity in the 2D Hubbard model, revealing non-standard superconducting gap features and implications for high-$T_c$ cuprates.

Contribution

It demonstrates that nematic and superconducting orders can coexist with broken $C_4$ symmetry, introducing admixture of $s$-wave pairing and altered gap structures.

Findings

Coexistence of nematic and superconducting phases identified.

Superconducting gap exhibits non-standard features and changed nodal directions.

Nematicity tends to develop in the optimally doped regime, influencing high-$T_c$ superconductors.

Abstract

We study the interplay of nematic and superconducting order in the two-dimensional Hubbard model and show that they can coexist, especially when superconductivity is not the energetically dominant phase. Due to a breaking of the $C_4$ symmetry, the coexisting phase inherently contains admixture of the $s$-wave pairing components. As a result, the superconducting gap exhibits very non-standard features including changed nodal directions. Our results also show that in the optimally doped regime the superconducting phase is typically unstable towards developing nematicity (breaking of the $C_4$ symmetry). This has implications for the cuprate high-$T_c$ superconductors, for which in this regime the so-called intertwined orders have recently been observed. Namely, the coexisting phase may be viewed as a precursor to such more involved patterns of symmetry breaking.